The wireless charging industry is in full gear with inexpensive charging docks and charging "receivers" that claim to supply 700ma of 5v USB power.
There is one that even "breathes" in blue light when the receiver is properly located above the dock. This sounds like something a bot could use as location feedback when rolling over a docking plate.
Starting with this in the power chain for a Raspberry Pi (A/B/B+/2) with Pi Droid Alpha based mobile robot, and with the right choice of storage I might be able to stop having to plug in my bot every few days. (Right now my RugWarriorPro bot will "run" for a few hours, or "sit quiet" under my desk for a day or two before the whining starts.)
Estimating Power Consumption:
- The Pi Droid Alpha power need (with external motor and external servo power) appears to be negligible,
- The Raspberry Pi (400-600ma), with active USB wireless (100-200ma), and with active camera (260ma) is probably around 1A total,
- A tilt/Pan setup with two SG90 micro servos (holding the Pi Camera and a Pololu 2470 IR ranging sensor ) probably requires around 800ma when moving and perhaps 1.3A when stalled at the limits (seems like needs some sort of current limiter would be smart.)
- Motors - YMMV, mine are 600ma max 1.2A stall max each, so that is 1.2A cruising and 2.4A between the time the bot hits a wall and the processor cuts the power.
A bot with this configuration would probably sit very quiet at 500-600ma, run around the room at 3A, and draw 4.7A having a "fully aware" nervous-breakdown.
Ouch - that means even if I figure out how to supply that peak load, just sitting quietly on the recharge pad takes up most of the available wireless charging power.
On the net, I see a 12000mah 4A power bank with five USB outputs for around $60 US. That could probably power the bot for 12 to 24 hours of "active" state. It would probably recharge in 20-24 hours if the bot was in total sleep, (but I don't have a real time clock (RTC) wakeup feature in the configuration).
If the bot remained always on, just sitting on its recharger, it would probably take the rest of a week to recuperate from an "all out party night"!
Wow, robots are power hungry souls.